Software Reuse: From Cloned Variants to Managed Software Product Lines

Many software systems are available in similar, yet different variants to accommodate specific customer requirements. Even though sophisticated techniques exist to manage this variability, industrial practice mainly is to copy and modify existing products to create variants in an ad hoc manner. This clone-and-own practice loses variability information as no explicit connection between the variants is kept. This causes significant cost in the long term with a large set of variants as each software system has to be maintained individually. Software product line (SPL) engineering remedies this problem by allowing to develop and maintain large sets of software systems as a software family.In this chapter, we give an overview of variability realization mechanisms in the state of practice in the industry and the state of the art in SPL engineering. Furthermore, we describe a procedure for variability mining to retrieve previously unavailable variability information from a set of cloned variants and to generate an SPL from cloned variants. Finally, we demonstrate our tool suite DeltaEcore to manage the resulting SPL and to extend it with new functionality or different realization artifacts. We illustrate the entire procedure and our tool suite with an example from the automotive industry.